From 1200832c6e850a17f36631f6492f953a1b39e6b8 Mon Sep 17 00:00:00 2001 From: Paolo Abeni <pabeni@redhat.com> Date: Fri, 24 Apr 2020 13:15:21 +0200 Subject: [PATCH] mptcp: fix race in msk status update Currently subflow_finish_connect() changes unconditionally any msk socket status other than TCP_ESTABLISHED. If an unblocking connect() races with close(), we can end-up triggering: IPv4: Attempt to release TCP socket in state 1 00000000e32b8b7e when the msk socket is disposed. Be sure to enter the established status only from SYN_SENT. Fixes: c3c123d16c0e ("net: mptcp: don't hang in mptcp_sendmsg() after TCP fallback") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> --- net/mptcp/subflow.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index fabd06f2ff45..71256f03707f 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -225,7 +225,7 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) subflow->icsk_af_ops->sk_rx_dst_set(sk, skb); - if (inet_sk_state_load(parent) != TCP_ESTABLISHED) { + if (inet_sk_state_load(parent) == TCP_SYN_SENT) { inet_sk_state_store(parent, TCP_ESTABLISHED); parent->sk_state_change(parent); } -- GitLab